Treatment of hydrocarbon oils



Jan. 3o, 1951 G. M. BROONER 2,539,808

TREATMENT OF HYDROCARBON OILS l Filed May 19,1947

INVENTOR` o. M. BRooNER ATTORN EYSW.

Patented Jan. 30, 1951 UNIT-ED 1ST-Ares PATENT OFFICE "TREATMENT lOld"HYDRARBON OILS l George'li. Brooner, Bartlesville, Ghia., lassigner to`Phillips Petroleum Company, a corporation of Delaware Application .May19, 1947, Serial No.1749j062 (Cl. l96-e29) 12 Claims.

`This'inventionrelates .to the treatment of sour hydrocarbon :oils tosweetenthesame. :In one of its 'more `,speciic aspects, `this inventionrelates to theremoval of @Water of .reaction ,from a sys- `:tenivutilized tin the syveeitening :of inatural gasofline, refinery:straight Krun and ucracked ggasolines, petroleurn Ysoli/ent naphthas,`liquefied petroleum gases, kerosenes, :and tne like, ato convert thelsulphur -compomds such as ,rnereaptans therein `which-areresponsiblerforbad odors or v`sourness landfor corrosiveness .ofthes,e:hydrocarbon materials. In another of ,itsfmore speciiic aspects,

lthis invention `relates to improvement in the fsweetening .ofmercaptan-'bearing lighthydrocai'-,

bon Amaterials by means Joi` a moistzsolid reagenxu comprising` acoppersalt and ahalide adsorbed on carriers.

:Such unrened petroleum products lcontain mercaptans commonly `icalledsour elements,

'which give :the product aan undesirable odor.

lThese compounds havesometimes been altered, bythe sri-called doctoiprocess, a laborious, V'cumbersome `and very `unecon'omical chemical`treatment with alkali plumbite and sulfur. In

some instances-e. `gnvvitha Vnatural gasoline, the

-sweetening "reaction has tbeen accomplished through the 'use ofalkaline hypochlorite solutions, but-thismethod, too,hasnot provedsatisfa'ctoryfin most cases. .Sometimes .the sour `elements seem jto beparticularly diliicult to `sweeten,'thereby requiring-large'quantitiesof Vthe reagent, and in .othencases theftreatment seems .to result Vinthe Iintroduction-into the oil :of undesirable yconstituents as badasthose originally present. Still other --methods have .been suggested forremoval -or'conversion vof the mercaptans but-almost'withoutexceptionthese methods Ainvolve numerous treating lsteps which demand 4such.close control-of theoperation-that the operfatigng .costs-are increasedrse-:much .as to render `such-methods uneeonomical.

Successful, economical Y methods 'of .sweetening :Whichhave 110Wcomeointo common use are yso- Lcalled copper,sweetenirlgcprocesses whichare now y.wellknown"in Vthe petroleum industry. One such process is.described by Buell vin U. ;S,Patent 12,094,485. .Inthat'typefoi-processazsolid treating "agent comprising `highly porous or adsorbent materialuch'as fullers vearth,charcoal,l or the like, is impregnated with aconcentrated solution of cupriochloride, or other -cupric ,halideJ or`of a water-soluble veupric salt, such -as cupric sulfate, and a halide,suoli as sodium-chloride. Astream comprising a mercaptanfsuch -asfa sourhydrocarbon material, -is contacted with said reagent by passing it inthe `liquid state, together with ydissolved oxygen-containing gas, Vatordinary temperatures through the reagent bed.

When -mercaptanszare passed irl-such a process Aover such acopperjhalideecontaining reagent the (2) ecuciorfinoir-owecuonao2h20Thus when free oxygen `is in solution withthe hydrocarbon `material. atthe time of sweetening, `reactions l and 2 occur `simultaneously and thereagent is maintained in an active state,

Fromreaction 1(2) however, it is apparent that another undesirablesituation 4arises in that considerable amounts of water are `formed inmaintenance of the reagent in an active state. This Water, unlesscarried out by the prod-uct stream, r'tends to Asaturate the Vreagentand frequently causes Vshutdovvns so that thejreagent can be dehydrated.y In attempting to overcome this trouble, it has been common `practiceto Vinstall in the feed stream, asalt filter, sand filter or other meansto remove any free or entrained Water from the feed vand following thisto preheat the feed stream `at some point ahead of the copper treatingtower. The preheating increases the capacity of the leed stream todissolve Water therein. Having a `greater capacity to ,dissolve Water,the feed stream will tend to dissolve more of .the water .ofreactionand. to carryv more of it out of the reagent tower than it would atlower temperatures. This practice however frequently fails to remove anamount of water sufcient to prevent the reagent from rapidly becomingsaturated.

An object of the invention is to provide an improvement for coppersweetening processes whereby the sweetening of a very sour lighthydrocarbon material by means of a solid reagent comprising a solutionof copper salt and a halide adsorbed on a solid adsorbent carriermaterial may be accomplished efficiently and economically for moreextended periods of time.

A further object of the invention is to substantially reduce the numberof shutdowns required in a copper sweetening unit to dehydrate thereagent.

A still further object of the invention is to provide an improvedprocess for converting mercapans to disuldes.

Still other objects and advantages will be apparent to those skilled inthe art from a careful study of the accompanying detailed disclosure.

I have now discovered an important improvement in converting mercaptansto disuldes, such as in the sweetening of a light or low boilinghydrocarbon material according to the previously described processutilizing a solid copper-containing reagent when the mercaptan contentof the sour hydrocarbon is so great that the resultant water producedtends to saturate the reagent in a relatively short period o time. Thisprocess of converting mercaptans to disuldes is generally used in thesweetening of a sour hydrocarbon stream wherein the mercaptanconcentration is relatively small. It may, however, be used in a processfor commercially converting mercaptans to disuldes wherein the mercaptanconcentration in relation to its hydrocarbon or other diluent which isnon-reactive with the reagent, is relatively large. The improvementcomprises recycling a portion of the product stream, cooling therecycled stream to precipitate water formed during the process ofconverting the mercaptans, passing it through a lter to separate outfree water, and adding the thus partially-dried recycled stream to thefeed stream. In this manner substantial amounts of water are removedfrom the recycled stream thus making the parts of Water per unit ofmaterial l treated substantially the same as that contained in theoriginal feed stream, but with a greater hydrocarbon volume andtherefore a capacity to remove or carry larger quantities of water insolution. Water may be removed from this recycle stream if desired, bycooling to a low temperature, and/or by contact with a suitabledesiccant, such as bauxite, silica gel, calcium chloride, or the like.This combined stream is then heated, to substantially increase themoisture absorbing potential of the stream, and is then passed throughthe copper reagent chamber. It will also be noted that by recycling aportion of the sweetened product a decrease in mercaptan content perunit of combined feed is obtained, although the same amount of mercaptanwould be passed through the reactor and the same amount oit' water wouldbe formed as if no recyclewere used. At the same time, however, therecycle sweet hydrocarbon will dissolve as much water proportionally asthe sour net charge with the advantage that it will not cause theformation of free water. By operation in this manner it is possible forthe copper reagent tank to be maintained on stream for Substantiallymuch greater periods of time without shutdowns for the purpose ofdehydrating the reagent.

Referring now to the accompanying diagrammatic drawing, the originaltemperature of the light or low boiling hydrocarbon oil which isintroduced into the system through line 6 and pump 'i is generallysubstantially that of the atmosphere. As it passes through heater 8 itis raised to a temperature between about 110 F. and about 130 F.,preferably about 120 F. In this manner the moisture absorbing potentialof the oil is substantially increased. Air or an equivalent gas which isneeded to furnish the essential oxygen for reactivation of the reagentis supplied to the system through line 9. Oxygen may be injected insteadof air but air is generally used for purposes of economy. There isnothing critical about the point at which the air is to be injected.Equally as efficient results are obtained by introducing air to the feedstream before heating as after the heating step. Usually the air isinjected at a pressure of between about 25 and about pounds per squareinch, but such pressure is limited only by the operating pressure limitof the plant equipment, usually from about 15 to about 100 pounds persquare inch. The amount should be sufficient to effect completeregeneration, based on complete conversion of mercaptans to disuldes, inaccordance with the previously discussed reactions. The heated feed isintroduced through line I0 into reagent chamber I2 where the reaction,above described, takes place. Sweetened hydrocarbons are removed throughline I3 and are directed to storage through line I4. A portion ofv thesweetened oil is drawn off through line I'I and is supplied todehydration means, such as cooler I8 and wateriilter I9. In cooler I3the temperature of the sweetened hydrocarbon stream is reduced to a 40point between about F. and about 90 F., but preferably to about F. Inthis manner the ability cf the hydrocarbon stream to carry dissolvedwater is reduced and substantial amounts of water which were formed inthe sweetening reaction and carried in the hydrocarbon stream areprecipitated. lIt is obvious that some additional water may be separatedfrom the oil stream by cooling below 60 F., and a desiccant may be usedin conjunction with or in place of such a cooler and lter, but in mostinstances it is unnecessary and uneconomical to do so. The hydrocarbonstream is then passed from cooler I8 to illter I 9 where the entrainedwater is removed. Any conventional material may be used in the filter tocoalesce and remove the condensed water out of the hydrocarbon stream. Iprefer to use either sand or salt. Water which has been removed from therecycle stream is drained off through line 2B while the stream is fedthrough line 2I to the feed stream in line 6. As the amount of mercaptanwill remain constant and the volume of water of formation is the same,saturation of the reaction chamber will be substantially reduced bymeans of the recycle portion because the portion of the stream which isalready sweetened will take up its portion of the water but will notcause water to be formed.

In the following table a material balance 'is shown for a coppersweetening operation with and without recycle when charging a sourgasoline weighing 260 pounds per barrel with a mer'- captan (RSH)content of 0.03 weight per cent and entering the unit at 80 F. and beingheated to F. The recycle operation utilizes a recycle ratio of 1:1. ,j

nimma "The vfollowing*table\'disclosesf'd'ata*vvliicwslfrovv clearly theeffect the invention has n1i"^"tlre'op\er atingtime l"forracopper-"sweetening unit These data based on `the preceding. material:balan'c'efare for "a unit utilizingl 2,000 "pounds *of reagent.

:.TabZ'eH f- .1 y WithoutRe- Operation With Recycle v .,cyde

Weten Pounds/Day:

In Charge Stream "6:2552 FormedinSweeteningrReacti .f 221.048

-`Total ,27..600 `27. 600 Water'Eliminatedz In sweetened?ProductrJ4 l'14% V976 .ByBecycle y Total 141976 14;!976 Water Remain t AP.ounds/Day i-v` 4. 200 12. 624 Penniss'ible Accumulation @Rc-g, .agent ,i260 260I.Days Operation Before Dehydratl ving Ye2 2o It is apparent that ia`great ideal ofv` eziibilityiis "possible "in thismethod of "controlling'the water content of thereagent byvarying"theamounts of the'sweetened*hydrocarbon which are recycled to the sour feed.stream,-theiamount ofwater removed from the recycle 'strearn,ari"d methods for tp'artiall-ydehydrating-fsaid "recycle lstream. 'fThe Ting hydrocarbon stream vwhichfcompr'ises the vsteps of' heating said stream, .furnishing oxygen tosaid stream, contacting said stream with a reagent comprising anadsorbent material impregnated with a copper salt and a halide in thepresence of a small portion of water, and withdrawing a sweetenedhydrocarbon from contact with said reagent; the improvement whichcomprises the steps of cooling a portion of said sweetened hydrocarbonso as to precipitatein `said hydrocarbon Water formed in the sweeteningof said hydrocarbon, separating said precipitated water therefrom,combining said sweetened and dehydrated stream with said sour feedstream, contacting said combined vfeed stream with said reagent, andremoving a portion of water formed during lsaid sweeteningQstep fromsaid reagent by dissolving said water in said sweetened and dehydratedportion f said feed stream.

2. In a process for sweetening a sour low boiling hydrocarbon 4streamwhich comprises the steps of heating said fstream to a temperaturebetween about 110 Fand about 130 F.,ffurnish ing oxygen to said stream,contacting said stream with a reagent comprising an adsorbent materialimpregnated with a copper salt and a halide in thepres'ence'pf asrna'llportionv o'f water, and 4withdrawing Ia 'sweetened `hydrocarbon 'fromcontact with said reagent; the improvement y which comprises the stepsof'fcooling'aportion 'of said sweetened hydrocarbon toatemperaturebetween'about" Frand about90" F. vso as 'to pre- 'cipitate insaid hydrocarbon wateriormed in fthe lsweeten'ing 'otsaidhydrocarbon,separating said precipitated "water therefrom, -combiningl'said sweetened and dehydrated stream withsaid sour feed stream,Wcontacting said combined feed "stream with'said Vreagrennand removing aportion'of water' formedduringsaidsweetening `step from said reagent by-dissolving saidwater insaid Asweetenedand dehydrated portion ofsaidieed stream.

3. 'In a process'ior sweetening a'sour low boilin'g hydrocarbon streamwhich comprises the "steps 'of 'heating'said streamv to `a temperatureVbetween about 11'0u F. and 'about 130 dissolving 'air in 'said stream,'contacting"'saidstream with'a'reagent comprising an adsorbent materialimpregnated "with a copper 'salt and a halide lin the 'presence vof aSmall portion 'of water, and withdrawing `a sweetened "hydrocarbon Vfromcontact with said reagent; the improvement lwhichcomprises thel stepsofcooling a portionof said sweetened hydrocarbon rto a temperature*betweenabout 60 .F.and about 90 F. so `as to precipitate insaidhydrocarbon water formed in tiie sweetening of said hydrocarbon, passing'said `'sweetened `hydrocarbon"through 'a vlterto remove said.precipitated Vwater from said stream, -corx'ibi'ningsaidsweetenedand'dehydrated stream w'thvsaid sor 'feed stream, contactingsaid combinedfeed stream withzsaid reagent, and removing'a portionofwateriformed during said'sweetening step from said reagent by dissolvingsaid water in said sweetened and dehydrated portion of said feed stream.

4. In a process for converting mercaptans to disuliides which comprisesthe steps of heating a hydrocarbon mercaptan-containing stream,furnishing oxygen to said stream, contacting said stream with a reagentcomprising an adsorbent material impregnated with a cupric halide in thepresence of a small portion of Water, withdrawing a disulfide-containingstream :from contact with said reagent; the improvement which comprisesthe steps of partially dehydrating a portion of saiddisulfide-containing stream, combining said partially dehydrateddisulde-containing stream with said mercaptan-containing stream,contacting said combined streams with said reagent, and removing aportion of water which is formed in the conversion of the mercaptant todisulde by dissolving said water in said partially dehydrateddisulfide-containing stream.

5. The process of claim 4, wherein oxygen is furnished by means of theintroduction of air to said stream.

6. In a process for converting mercaptans to disuldes which comprisesthe steps of heating a hydrocarbon mercaptan-containing stream, fur--nishing oxygen to said stream, contacting said stream with a reagentcomprising an adsorbent material impregnated with a copper salt and ahalide in the presence of a small portion of water, and withdrawing ahydrocarbon disulfide-containing stream from contact with said reagent;the improvement which comprises the steps ci' partially dehydrating aportion of said disulde stream, combining said partially dehydrateddisulfide-containing stream with said mercaptancontaining stream,contacting said combined stream with said reagent, and removing aportion of water formed in the conversion of the mercaptans todisulfides by dissolving said water in said partially dehydrateddisulfide-containing stream portion. l

7. The process of claim 4, `wherein oxygen is furnished by means of theintroduction of air to said stream.

8. Ina process for sweetening a sour low boiling hydrocarbon streamwhich comprises the steps of heating said stream, furnishing oxygen tosaid stream, contacting said stream with a reagent comprising anadsorbent material impreg nated with a cupric halide in the presence of.a small portion of water, and withdrawing a sweetened hydrocarbon fromcontact with said reagent; the improvement which comprises the steps ofcooling a portion of said sweetened hydrocarbon so as to precipitate insaid hydrocarbon water formed in the sweetening of said hydrocarbon,separating said `precipitated water therefrom, combining said sweetenedand dehydrated stream with said sour feed stream, contacting saidcombined feed stream with said re agent, and removing a portion of waterformed during said sweetening step from said reagent by dissolving saidwater in said sweetened and dehydrated portion of said feed stream.

9. In a process for sweetening a sour low boiling hydrocarbon streamwhich comprises the steps of heating said stream to a temperaturebetween about 110 F. and about 130 F., dissolving air in said stream,contacting said stream with a reagent comprising an adsorbent materialimpregnated with a cupric halide in the presenceof f tion of waterformed during Vsaidsweetening step from Said reagent by dissolving saidwater in said sweetened and dehydrated portion of said feed stream.

10. The process of claim 9 wherein said filter is a sand lter.

11. rIhe process of claim 9 wherein said lter is a salt filter.

12. In a process for sweetening a sour low boiling hydrocarbon streamwhich comprises the steps of heating said stream, furnishing oxygen tosaid stream, contacting said stream with a reagent comprising anadsorbent material imp-regnated with a copper salt and a halide in thepresence of a small portion of water, and withdrawing a sweetenedhydrocarbon from contact with said reagent; the improvement whichcomprises.. the steps of partially dehydrating said sweetened stream,combining said sweetened and partially dehydrated stream with said sourfeed stream, contacting said combined feed stream with said reagent, andremoving a portion of water formed during said sweetening step from saidreagent by dissolving said water in said sweetened and partiallydehydrated portion of said feed stream.

' GEORGE'M. BROONER.

REFERENCES CITED The following references are of record in the file `ofthis patent:

1. IN A PROCESS FOR SWEETENING A SOUR LOW BOILING HYDROCARBON STREAMWHICH COMPRISES THE STEPS OF HEATING SAID STREAM, FURNISHING OXYGEN TOSAID STREAM, CONTACTING SAID STREAM WITH A REAGENT COMPRISING ANADSORBENT MATERIAL IMPREGNATED WITH A COPPER SALT AND A HALIDE IN THEPRESENCE OF A SMALL PORTION OF WATER, AND WITHDRAWING A SWEETENEDHYDROCARBON FROM CONTACT WITH SAID REAGENT; THE IMPROVEMENT WHICHCOMPRISES THE STEPS OF COOLING A PORTION OF SAID SWEETENED HYDROCARBONSO AS TO PRECIPITATE IN SAID HYDROCARBON WATER FORMED IN THE SWEETENINGOF SAID HYDROCARBON, SEPARATING SAID PRECIPITATED WATER THEREFROM,COMBINING SAID SWEETENED AND DEHYDRATED STREAM WITH SAID SOUR FEEDSTREAM, CON-